Friction elements



C. BOCKIUS E T AL FRICTION ELEMENTS Filed Nov. 20, V193,5

3 l Je .,s-Sheet l Sa., 20, w38.

c. BocKlUs Er AL 2,330,520

FRICTION ELEMENTS Filed NOV. 20, 1935 3 Sheets-Sheet 2 p. 2U, 193. c.Bocmus Er AL l 130,520

FRIGTION ELEMENTS Filed NOV. 20, 1935 3 SheetsSheet 3 Patented Sept. 20,1938 UNITED STATES PATENT OFFICE Cook, Haledon, N. J.,

assignors to Raybestos- Manhattan, Inc., Passaic, N. J., a corporationof New Jersey Application November 20, 1935, Serial No. 50,802

Claims.

This invention relates to improvements in friction elements for use asclutch facings, brake linings and the like, and to a novel method andapparatus for making the same. The novel prod- 5 uct of this inventioncomprises a structure having no splices, staples or other hardprojecting areas of juncture, constructed by endlessly winding fibrousyarn or roving into an endless Wound structure.

The invention will be described with particular reference to itsembodiment in a clutch facing, but it is to be understood that theinvention embraces brake linings as well as clutch facings.

Among the objects of this invention are to provide an endless frictionfacing devoid of splices, thus eliminating variations in density andinsuring uniformity of the facing throughout its entire contact area; toprovide a facing having an unusually high resistance to centrifugalforce; to provide a facing especially adapted for use with crimpedpressure plates; to provide a structure which lends itself toeconomicalmanufacture, since there is no cutting or waste of material other thanthat lost in the grinding operation, which is negligible; to provide astructure in which, due to the peculiar spider-web method of winding andthe manner in which the wave form strands fall over and overlap whilecuring, there is no danger of ply separation; to provide a structure inwhich the possibility ,of scoring is eliminated since it has nosymmetrical pattern, and in general to provide an improved frictionelement for the purposes herein described.

Resistance to centrifugal force is becoming more and more import-nt withthe growing popularity of high speed engines and clutches, which may bedisengaged at these high speeds, with the result that the side holdingpower of the pressure plate and flywheel plate are removed. 40 Thisaction brings a very high centrifugal force to bear upon the facingwhich it must resist with its own strength. Since the clutch facing ofthe present invention is devoid of splices, greater resistance tocentrifugal force is obtained and hence the friction facing of thisinvention is especially adapted for use at the present time.

This invention overcomes the objection of straight wound yarn, in thatthe loops of each turn, being progressively ahead or behind the previousloops, develop great strength circumferentially and radially. i

Facings have been constructed by Winding yarn so-called endlessly,wherein the yarn or roving is wound upon itself spool-like without anyattempt being made to obtain controlled placing of the yarn withreference to the location of the yarn in the previous turn. These havebeen found to be deficient in strength to retain the rivets and thestrands may have a tendency to unwind or unravel, furthermore the facingmay 5 be sheared into separate concentric rings in line with the rivetcircle or other sections of thev ring which may show a weakness o-fadhesion circumferentially.

The construction provided in our pattern pre- 10 vents any possibilityof the facing shearing circumferentially at any place, including therivet circle.

Friction elements made in accordance with the present invention do notnullify the action of 15 crimped pressure plates as do other types offacings which, due to their rigidity, provide no cushioning action totake up the tolerances and irregularities of manufacture of the metalparts of the clutch.

From the viewpoints of economy of manufacture, while the frictionelement of the present invention has all the advantages of the Woventype, the expense of weaving is saved. In addition, since the elementhas no symmetrical pat- 25 tern the possibility of scoring iseliminated, as opposed to some types of woven structures heretoforeproposed, (when the woven material is coned to form a ring) which haverelatively high knuckles or loops in the Warp low each othersuccessively in one circumferential path, causing undue local abrasionor scoring.

The method of manufacturing the product of this invention permits theuse of types of yarn which might be .impossible to pass through a loomor a friction calender in other types of manufacture.

With the foregoing and other objects in view, we have devised a newfriction element and a new and improved method and apparatus for makingsame, as Will be more fully disclosed in connection with theaccompanying drawings.

In the drawings, 45

Fig. 1 is a side elevational view Iof a'machine for carrying out ourinvention.

Fig. 2 is a top plan view of the apparatus shown in Fig. 1.

Fig. 3 is an end elevational view of the machine 50 shown in Figs. 1 and2.

Fig. 4 is a fragmentary face view of one of the friction facingscomprising our invention.

Fig. 5 is an edge View of the facing shown in Fig. 4.

threads which fol- 30 Fig. 6 is a schematic view of the electricalwiring used in our machine.

Our invention involves the forming of friction elements by winding yarnor roving on a suitable form. 'Ihe yarn or roving may be entirely offiber, such as asbestos or cotton or combinations of different types offiber, the preferred yarn or roving being asbestos with suncient cottonto give it the required strength. Another common type of yarn or rovingused in making friction elements is a combination of metal wire, such asbrass or copper, with a fibrous material, such as asbestos or cotton orboth. Sometimes this type of yarn is formed by winding the fibrous yarnor roving about the wire or the wire and brous yarn are twistedtogether, and this twisted yarn may comprise more than one strand ofwire or more than one strand of yarn, as for instance two stl ands ofwire. and three strands of fibrous yarn or roving twistedtogether. Afterimpregnating the yarn or roving with a suitable binder it is preferablydried and Wound. The .element after being wound is preferably compressedin a suitable mould to give it the desired density and shape.

Referring in detail to the drawings, I indicates a frame for supportingthe machine comprising our invention, said frame being carried bysuitable legs or standards 2 and 3. Referring more particularly to Fig.2, an electric motor 4 may be mounted upon frame I and may drive, bymeans of belt 5, pulley 6 which in turn is mounted upon shaft 1. Shaft Iis the input shaft of a conventional speed reducer 8 which is alsomounted upon frame I. An output shaft 9 may project from speed reducer 8and -a chuck I 0 may be mounted upon the end thereof.

Chuck I0 comprises stationary plates II and VI2, being the rear andfront plate respectively, said last mentioned plate being provided witha plurality `of radial slots I3, shown best in Fig. 3. A pin projectsoutwardly through each of said slots. interposed between plates I I andI2 is a circumferentially movable plate I5 which is provided with aplurality of circumferentially spaced recesses I6. The arrangement issuch that pins I4, initially all disposed in a circle, are movable inunison radially in said slots, the diameter of the circle formed bythepins increasing or decreasing depending upon the direction of movementof plate I5. For instance, if it is desired to increase the diameter ofthe pin circle the plate I5 may be moved in one direction by means ofthe implement II which is removably insertable in any of the recesses I6or if it is desired to decrease the pin circle diameter, the plate ismoved in the opposite direction.

A shaft I8, a continuation of shaft 9, projects from the opposite sideof the speed reducer -and carries at its end, a bevel gear I9 whichmeshes with bevel pinion 20 carried at one end of shaft 2I. Shaft 2I maybe journalled in sleeve 22 which in turn is supported upon frame I. Aneccentric 23 is carried at the opposite end of shaft 2I. Eccentric 23comprises plates 24 and 25, the former being concentrically mounted uponshaft 23. Plate 25 is pivotally secured to the face of plate 24, as at26 (Fig. 1), and is. provided with an arcuate slot 21, the radius ofcurvature of which is equal to the distance betwen the pivot 26 and theslot. A locking screw 28 is mounted upon plate 24 and projects throughslot 21 whereby plate 25 can be locked at any desired eccentric positionwith respect to plate 24.

A connecting rod 29 is pivotally attached to the center of plate 25, as30. 'Ihe opposite end of by passing the same through a drier 5I'.

connecting rod 29 is pivotally secured to slide rod 3I which is slidablypositioned in slide bearings or guides 32 and 33, which in turn arecarried on standards 34 and 35, respectively, mounted upon frame I. Itcan readily be seen that upon motion of gear I9, shaft 3| will be givena reciprocating motion, the frequency of reciprocation of which isdependent upon the gear ratio of gear I9 to pinion 20, and the stroke ofwhich is dependent upon the throw of the eccentric, which, of course, isadjustable by means of plates 24 and 25.

A bracket 36 is mounted,by means of bolt 31, upon the upper face ofslide-rod 3| intermediate supports 34 and 35. A pin 38 is positionedbetween the upstanding portions of bracket 36 and an arm 39 is swingablymounted on said pin. Pressure roll 40 is rotatably mounted adjacent thefree end of arm 39 and guide roll 4I is mounted at the end of said armadjacent roll 40. Arm 39 is free to swing radially toward chuck I0, asshown in .full lines in Fig. 3, or said arm may be swung to the positionshown in dotted lines in said figure in which position it is supportedin substantially upright position by stop 42 carried by rod 3l.

A resilient metal band 43 serves as a support for a friction facing 44being Wound on the machine. The band 43 carries a bolt 45 at one end anda slot (not shown) at the other, said bolt being positionable in saidslot.

' In preparing the machine for the winding of the facing 44, a band 43of appropriate length is selected. The band is initially rolled to adiameter less than the inside diameter of the facing.` Plate I5 isrotated to cause pins I4 to assume a circle less than the insidediameter of the facing. 'Ihe band 43 is then positioned over said pinsand plate I5 is manipulated to cause pins I4 to move radially outwardly.In so doing band 43 is expanded, bolt 45 moving in the slot at theopposite end of the band until said bolt abuts the end of the-slot.'I'he band, at this period is of a diameter equal to the inside diameterof the facing and nut 46 is tightened. Of course, for facings ofdifferent inside diameters different bands 43 must be used.

The wound structure 44 is removed from the Winding machine by rotatingdisc I6, thereby reducing diameter of spring steel band 43, which allowsstructure 44 to be remo'ved.

A standard 41 is mounted upon frame I at one side of chuck II), saidstandard carrying a guide 48 adjacent its end. At the end or top of saidstandard a. roller 49 is mounted. The guide 48 and guide roller 49 areadapted to guide one or more strands 50, of which the facing 44 isconstructed, from a source of supply (not shown) to gu'ide roller 4I,and over said roller around pressure roll 40 to band 43. Prior topassing the strand or strands 50 over guide roll 49, said strand orstrands may be `passed through a bath of saturant 49' carried in asuitable vat 48', said strands being carried around roller 50 immersedin said bath. After leaving the bath 49 said strand or strands may bedried as, for instance, A pair of disks 5I may be mounted concentricallyupon the end of shaft 9, both of said disks being dished to provide anannular groove between the peripheries thereof. The purpose of disks 5Iis to clamp or pinch thevends of the strands 50 to anchor the sameduring the winding stage.

The strands 50 may comprise asbestos roving or asbestos ryarn with orWithout wires, the strands being given one or more coatings or rubber orother like cement. The strands may then be dried and subsequently woundon spools or bobbins (not shown) from whence they are fed to ourmachine. In feeding the strand to the machine, the strands may be passedforwardly singly or two or more strands may be simultaneously wound.Each strand 50 may comprise a single strand of roving or yarn, or two ormore single strands may constitute one unit strand 50.

In carrying out the process of our invention, when `motor 4 isenergized, shaft'9 is driven at a predetermined speed thereby rotatingchuck l0. One or more unit strands 50, previously threaded through guide48 and over rolls 49, 4| and 40 anchored between the disks 5|, arethereby wound upon the form or band 43. However, simultaneously with therotation of shaft 9, shaft I8 is rotated thereby rotating gear I9,which,

through the agency of pinion 20, drives shaft 2| and disks 24 and 25,the angular velocity of said disks being dependent upon the ratio ofgears |9 and 20. Upon rotation of disks 24 and 25, shaft 3| isreciprocated thereby reciprocating arm 39. Arm 39, of course, carriesrolls 4l) and 4| and hence strands 50 are moved axially over form 43simultaneously with the winding of said strands. In thismanner facing 44is built up', the thickness of which is dependent upon the stroke of theshaftvor rod 3| and the number of waves or zig zags being dependent uponthe gear ratio of gears I9 and 20. In this case we use a gear ratio of3% to 1; this gives a pattern in which the loops are ahead of theprevious turns or the Winding form makes 15 revolutions before'a loop isin line with a loop previously wound. As the facing 44 is being wound,roll 40 bears upon the periphery of the facing tending to knit orcompact the strands, the previous treatment of said strands causing saidstrands to adhere to each other.

A sprocket wheel 52 is mounted upon shaft I8 and drives sprocket chain53 which in turn drives sprocket wheel 54 mounted upon input shaft 55 ofspeed reducer 56. Speed reducer'56 is mounted upon the lower side offrame and has an output shaft 51. The speed ratio of the input shaft 55to output shaft 51 is in the neighborhood of 300 to 1, that is, 300revolutions of shaft 55 results in 1 revolution of shaft 51. A clutchplate 58 is mounted upon the end of shaft 51 which makes frictionalengagement with plate 59 through the agency of friction material 60.Plate 59 is mounted on one end of shaft 60 journalled in bearings 6| and62. A collar 63 is mounted upon an intermediate portion cf shaft 60 anda coil spring urges said collar and hence shaft 68 and plate 59 towardplate 58 maintaining the same in non-slipping engagement.

A disk may be rigidly secured to bearing 62 and is provided with indicia66 which divides the disk into a series of equal divisionscorrespondingto the number of revolutions of shaft 55 or shafts 9 andI3.v As arm 61 is mounted on the end of shaft 60 and is adapted totravel adjacent the faces of disk 65 during revolution of shaft 60. Anelectric switch 68 is mounted adjacent shaft 60 immediately behind disk65, said switch having a plunger 69. A lug 10 is rigidly secured toshaft 60 and upon counterclockwise motion of said shaft said lugisadapted to depress plunger 69. An arm 1| is loosely mounted upon shaft60 and carries knurls or teeth adapted to engage with knurls or teeth 12carried on the periphery of disk 65 whereby arm 1| may be presetat adesired position upon the periphery of disk 65. Arm 1| also carries aswitch having a plunger 13,

which, when arm 61 rotates to the position occupied by arm 1|, isdepressed by roller 14 carried at the end of arm 61. A box 15 contains arelay which is utilized in automatically starting and stopping motor 4,as will be hereinafter more fully described. A

Referring particularly to Fig. 6, a diagram,- matic view of the electricconnections for the automatic control of the machine is shown. A sourceof electric current is indicated at 16. One side of the line isconnected directly by means of conductor 11 to motor 4. The oppositeside of the line is connected through switch points 11 to the oppositeside of the motor, switch points 11 comprising a portion of themechanism contained in box 15. A solenoid 18 is also contained in box15, a movable vplunger 19 comprising the core of said coil. Coil 18 isconnected across the rline through switch 6B, which is normally open.One end of coil 18 is connected through switch points 80 and switch 13to line 11, switch 13 being normally closed. Core 19 carries at itsupper portion bridging plate 8| which is adapted to bridge terminals 11and at its lower end bridging plate 82 adapted to bridge points 80.

In operation, switch 13 is normally closed and switch 68 is normallyopen. The radial depth of the facing 44 is predetermined and the numberof revolutions of the chuck will also be determined. The machine willthen be set to perform the predetermined number of revolutions bysetting arm 1| at said number upon scale 66. Arm 61 is then moved tozero upon said scale which moves lug 10' into contact with plunger 69momentarily closing switch 68. Upon'closing switch 68 coil 18 isenergized moving plunger 19 upwardly, bridging switch points 11 and 89and closing the motor circuit. Shortly after switch 68 is closed itagain opens but inasmuch as points 80 are bridged coil 18 will still beenergized. When chuck I0 rotates the necessary number of revolutions arm61 will have moved to the position where roller 14 contacts plunger 13thereby opening said switch. This, of course, opens the holding circuitthereby breaking the motor circuit and stopping the motor. f

After winding the structure 44 the same may be compressed to theapproximate dimensions of the finished facing. The compacted structuremay then be placed in molds (not shown) and further compressed and curedto the finished state thereby providing an endless friction elementwhich is ideally adapted for use as a clutch facing or for like uses. Ofcourse, after curing the facings the same are ground and baked or heattreated in the usualv manner and rivet holes may be punched therein.

In impregnating the strands 50, as has been hereinbefore described, anyof the well known saturants or binders used in the manufacture offriction materials can be utilized, such as, rubber, latex, oxidizableoils, resins, bitumens, colloidal mixtures, or the like. If desired, thefirst windings of the structure 5 may be saturated 'with one saturant ora predetermined concentration of a predetermined saturant and the lastwindings may be saturated with a different saturant or a differentconcentration of the same saturant, so as to impart different frictionalcharacteristics to different portions of the facing.

While we have specifically described the invention utilizing yarn orroving impregnated.

with a suitable binder prior to winding, it is to be understood that theinvention in its broader aspects includes the winding of unsaturatedyarn or roving in which case the wound structure would be saturated aswell as the step of saturating or impregnating the Wound structure witha suitable binder even when made from previously impregnated yarn.

Also, it is to be understood that instead of compressing the yarnradially with a roller While it is being Wound for the purpose ofcompacting the wound structure means may be provided for impartingtension to the yarn as it is being Wound to retain the structure in itswound shape,4

We claim as our invention:

1. A method of making a friction facing which comprises, winding apreviously impregnated strand comprising asbestos to form an annularring, and simultaneously with said winding step, guiding said strand ina reciprocating manner to dispose each loop of said strand in pluralwave fashion over an adjacent loop thereof and lightly compressing andcompacting each loop against an adjacent loop of said ring by aid of arolling contact during the Winding step.

2. A method of making a friction facing which comprises, winding apreviously impregnated stran comprising asbestos to form an annularring, simultaneously with said Winding step, guiding said strand in areciprocating manner a plurality of times for each loop of said ring todispose each loop of said strand in wave fashion upon an adjacent loopthereof and lightlyl compressing and compacting each loop against anadjacent loop of said ring by aid of a rolling contact during thewinding step.

3. A device for making endless wound friction facings comprising incombination, a frame, a shaft mounted upon said frame, a form mountedupon said shaft, means for rotating said shaft to Wind an asbestosstrand upon said form, means for guiding said asbestos strand to saidform, and means synchronized with the movement of said shaft and formfor reciprocating said guiding means a plurality of times for eachrevolus tion of 'said form, said reciprocating means comprising aneccentric, means for driving said eccentric from said shaft, and aslidable member operatively connecting said eccentric and said strandguiding means.

4. A method of making a friction facing which comprises, winding a,previously impregnated strand comprising asbestos in a relatively loosefashion to form an annular ring, and simultaneously with said windingstep, guidingsaid strand in a reciprocating manner to dispose each loopof said strand in a wave form which repeats itself a plurality of times,and compressing and lightly compacting each loop radially against anadjacent loop by the aid of substantially frictionless radial contactduring the Winding step.

5. A method of making a friction facing which comprises winding apreviously impregnated strand comprising asbestos to form an annularring and simultaneously with said winding step, guiding said strand in areciprocating manner to dispose each loop of said strand in plural wavefashion over an adjacent loop thereof, correlating the winding andreciprocating guidance of the strand so as to dispose the respectivewaves of adjacent loops out of phase and compressing and lightlycompacting each loop radially against an adjacent loop withoutsubjecting the strands of said loops to appreciable tension.

' CHRIS BoCKIUs.

JUDsoN A. cooK.

